Not sure about how much power I need in a PSU. I generally use my computer for basic productivity (MS Office, Quark), surfin', some multimedia and games (nothing extremely intense - mostly backgammon and poker but also games such as Sims2). Would 350W be adequate?

This will depend largely on your choice of graphics cards and drives. It's not the software you use that consumes power, it's the hardware you've fitted in order to do it.

If you're running hefty games on a small on-board graphics chip, you don't need loads of power. But, if you've just bought the latest 256Mb graphics card with dual fans on it, then you'll need more.

Same goes for drives - running a small hard disk and a plain CDROM won't take much effort but running twin 200Gb SCSI drives with a RAID controller card and a pair of DVD-writers will take a lot more.

If your current PC (I'm assuming your talking about your existing PC) is working ok, then you don't need to upgrade your PSU.

If your upgrading, then as DJ says, we'll need to know what your putting in it to guesstimate an appropriate Wattage.

If however your replacing your existing PSU 'cos it's duff, then get either one of equal or if the cost is ok one of higher wattage than your existing one.

Id say usually 400W is the max youll ever need, Unless you have a Graphics card that has its own power connector, and has a requirement of like 480W.

350W is good enough, the average system might use about 200W.

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The power usage chart, (From tigerdirect.com or .ca >>Build it yourself guide)
Component Wattage Required

Motherboard 15-30
Low-End CPU 20-50
Mid To High-End CPU 40-100
RAM 7 per 128MB
PCI Add-In Card 5
Low To Mid-Range Graphics 20-60
High-End Graphics 60-100
IDE Hard Drive 10-30
Optical Drives 10-25

You'll also find that better quality PSUs don't need to have the same power output as cheaper brands. I'd much rather have a quality 350W PSU instead of a no-name brand 550W supply. I've had too many die on me to risk it!